1. Field of the Invention
The present invention relates generally to nanoscale electromechanical (NEMs) devices, and in particular, to a method, apparatus, and device for a micro-fluidic embedded polymer NEMs force sensor and vacuum insulated polymer based micro-biocalorimeter integrated with microfluidics.
2. Description of the Related Art
(Note: This application references a number of different publications as indicated throughout the specification by reference numbers enclosed in brackets, e.g., [x]. A list of these different publications ordered according to these reference numbers can be found below in the section entitled “References.” Each of these publications is incorporated by reference herein.)
The development of microcantilever force sensors has enabled development in the field of atomic force microscopy (AFM). AFMs are important tools in nanoscience and have further led to the development of cantilever based sensing, including a wide range of scanning probe microscopies (SPM), and many different forms of static (that is non-scanned) sensing. SPMs are used to image local forces arising from magnetic and magnetic resonance interactions; forces from local electrostatics, surface potentials, surface temperatures, and chemical bonding; and forces from many other local origins. Similarly, applications for non-scanned microcantilever sensors are equally diverse, including infrared imaging, nanocalorimetry, vapor- and liquid-phase chemisensing, electrometry, mass detection, etc.
However, at microscale dimensions, there are limits with respect to the level of frequency achievable and the level of sensitivity attainable. In this regard, the standard approaches used to make microelectromechanical systems (MEMS) cannot provide access to the nanoscale, where very large improvements in sensitivity can be attained [1]. Recent demonstrations and applications of the unprecedented sensitivity available from nanoelectromechanical (NEMS) devices include milestones such as sub-single-charge electrometry[2], single-electron-spin paramagnetic resonance [3], zeptogram-scale mass sensing [4], zeptonewton-scale force sensing [5] and subfemtometer displacement sensing [6]. In fact, with these continuing advances, NEMS sensors are rapidly converging towards the ultimate, quantum limits of force and displacement detection [7].
However, in contrast to MEMS, NEMS devices are still largely pursued only within the province of specialists. A current barrier to their practical development and widespread use is the difficulty of achieving sensitive displacement transduction at the nanoscale. Beyond the initial challenges of fabricating ultra-small mechanical devices, successful realization of NEMS involves addressing the doubly hard challenge of realizing very high frequency displacement sensing while attaining extreme subnanometer resolution. This is not straightforward; approaches to displacement transduction commonly used for MEMS generally are not applicable to NEMS [8]. For example, the efficiency of capacitive detection precipitously decreases at the nanoscale, and the signal is typically overwhelmed by uncontrollable parasitic effects.
Existing prior art techniques used to measure forces exerted by biological structures have been primarily limited to optical measurements. For optical readouts, diffraction effects become pronounced when device dimensions are scaled far below the wavelength of the illumination used. Furthermore, existing readouts for scanned probe microscopy cantilevers are predominantly based upon external (that is, off-chip) displacement sensing systems that, typically, greatly exceed the size scale of the cantilever sensors themselves. The most common SPM readouts are optically based, involving simple optical beam deflection or more sensitive interferometry. By comparison, only a relatively small subset of efforts has focused upon development of self-sensing nanocantilevers.
In addition to the above, the ability to measure forces exerted by biological specimens have encountered significant limitations. In this regard, prior art techniques have focused on optical measurement techniques. In such an environment, the amount of resolution attainable is limited. Further, prior art techniques fail to provide an efficient mechanism to deliver individual cells to specific force sensors and fail to precisely control the chemical environment around a cell under study. In addition, prior art delivery and control systems fail to maintain the viability of the biological sample under study while providing a mechanism to extract signals from a force sensor to a computer for readout and analysis.
In view of the above, what is needed is a NEMs force sensor for use in biological applications that can be used in an efficient and controlled environment.
In addition to the above, calorimeters are used in the prior art to detect enthalpy change of chemical and biological reactions. However, measurement sensitivity of microfabricated calorimeters/thermometers fail to achieve the measurement sensitivity compatible to that of large scale calorimeters. Such a lack of measurement sensitivity is determined by the sensitivity of the thermometer and capability to maximize the signal with good thermal isolation. However, the prior art has failed to increase sensitivity to minimize the heat loss of the sample. Accordingly, what is needed is a microcalorimeter that is useful in biological applications and that provides sufficient measurement sensitivity.